Magnetic Measurements in LHD

The stored energy and plasma currents measured with magnetics have been analyzed in Large Helical Device (LHD). The stored energy has been measured with diamagnetic loops inside vacuum vessel and compensated by direct measurements of eddy currents flowing some structures because there are several complex structures mutually coupled with the toroidal flux and the eddy currents on helical structures due to a variation of poloidal flux produce the toroidal flux. The stored energy reached about 20 kJ at ECH plasmas (84GHz, <350kW, <500ms) during the first operational cycle experiments, and then the confinement time was more than 200ms. The net toroidal currents were observed up to 3kA. The observed currents have been compared with bootstrap currents predicted by 3-D MHD Equilibrium calculation because the observed currents depend on the stored energy and the direction is consistent with theoretical prediction. The more detail analysis on plasma currents will be made by profile measurements with Thomson scattering and so on at the second operational cycle experiments. Also an anisotropy of plasma pressure will be investigated with diamagnetic and profile measurements.